A key component to the past and future success of this Program Project is the DNA Synthesis Core Facility, the role of which is to provide ready access to highly purified, site-specifically adducted oligonucleotides to be used in three Projects for mechanistic, structural and biological evaluation, respectively. As such, the DNA Synthesis Core Facility plays a crucial role in all three research programs within the Program Project. Synthetic methods developed in Project 1 are utilized by the DNA Synthesis Core Facility for the preparation of the desired site-specifically modified oligonucleotides. The core is also responsible for the purification of the oligonucleotides and initial chemical analysis to verify its composition. Over the past nine years, Dr. Constance M. Harris served as Director of the DNA Synthesis Core. The core laboratory funds 1.5 technicians to aided Dr. Harris. The remainder of the half-time technician is funded through cost-sharing and other University resources. Dr. Harris will retire in August of 2001, after which time Dr. Carmelo J. Rizzo will assume the core laboratory responsibilities as Director. Dr. Rizzo has extensive experience in the synthesis of nucleosides and phosphoramidites and has been involved in oligonucleotide synthesis in the past. To insure a smooth transition of responsibilities, Dr. Rizzo has already assumed a role in the operation of the DNA Synthesis Core and Dr. Harris has agreed to be a consultant after her retirement.